Hygroscopic regulating device



June 1 1926.

w. B. HODGE HYGROSCOPIC REGULATING DEVICE Filed may 19,

12% 3 2 Sheets-Sheet l June 1,1926. 1,587,314

W. B. HODGE HYGRoscoPIc REGULATING DEVICE Filed May 19, 1923 2 sheet's-sheet 2 zii.

67 l sa 40 4l t?? 4a 70 y 4fl 72 v f l 60 53 e l 1 l 'ab 58 Patented June l, 1926.`

r UNITED STATES WILLIAM E.,HoDeE, or CHARLOTTE, Noazrn CAROLINA.

meaoscorrc EEGULATING nEvIcE.

Application led May 19, 1928. Serial No. 640,283.

This invention relates to automatic con-` plied to a hygrostat of the well known relay motor type.

The object of the invention is to provide automatic means deriving power from the pressure fluid used in the automatic control device, put into action by changes of condition in the control system, and when put into action functioning to clean or remove obstruction from certain arts of the device which have shown a ten ency to bccome clogged.

The referred embodiment of the invention isi lustrated in the accompanying drawin s in which:-

i'g. 1 is a front elevation of the control device and its case, certain parts being broken awa to show the construction'. In this view tlie source of pressure fluid and the controlled device with their connections are diagrammatically represented F Fig. 2 is a section on the line 2 2 of Fig. 3 is a view on an enlarged scale artly in section and partly in elevation s owing the operative parts of the automatic control device. In this view certain parts are broken away to reduce the length of the gum;

Fig. 4 is an enlarged fragmentary section showing the position assumed by the particular 4cleaninfg mechanism when the system is shut down.

The invention is shown as applied to that well known type of automatic control device in which a responsive element operates to open and close a leak port connected with a diaphragm chamber. Pressure fluid, customarily compressed air, is constantly fedto this diaphragm chamber through a restricted feed port and the relation of thc vsize of the leakport to the size of the restricted ort is such that when the leak port is opened the diaphragm collapses and when it is closed the diaphragm is distended.

This diaphragm operates a combined inlet and exhaust valve which operates to admit and exhaust pressure to and from a controlled motor. This may, for example, be a diaphragm motor which actuates u Vthe tubular arm 27 being such that its valve, the valve in turn controlling the action of a humidifying device or a heater, according to. the particular installation In the drawings, 6 represents a casing provided with a transparent front 7 and ivided into two compartments b a vertical partition 8. The s ace to the rlght of the partition 8 is provided at its bottom with an air inlet protected by a screen 9, and is provided at its top with an air outlet 10. Near the top of this passa'ge is a fixed' support 11 and near the bottom is a longitudinally slidable support 12 which is vertically adjustable by a screw 13 swiveled therein and threaded in a block 14. The screw 13 may be turned by a socket wrench or key applied t0.the square end 15. v

he purpose of adjusting the support l2 is to adjust the tension on a hygroscopic member 16 of any well known form which extends between the fixed support 11 and the adjustable su ort 12.

At, or near mi en h of the h groscopic member 16 a clamp 1 is attache 18 is pivoted at 19 within the case 6. This lever 18 is connected with the clamp .17 by a link 2O which passes through an aperture in the partition 8, and is pivotally connected both to the lever 18 and the clamp 17..

The lever 18 terminates in a pointer 21 `which reads against a graduated scale 22.

In the case of a hygrostat, this scale mivht indicate any function of atmospheric umidity and temperature. In hygrostats for use in textile mills, it is desirable to indicate regain. For best effect, therefore the hygroscopic element 16 's composed of thc fiber treated in the mill, and the scale is graduated in terms of regain on such ber, and as a result, the scale and pointer will indicate the moisture in such liber with reasonable accuracy.

Pivoted at 23 to the lever 18 a short distance above its fulcruxn 19, is an arm 24 carrying at its end a valve disc 25. The

A lever downward swinging motion of the arm 24 relatively to lever 18 is limited b a stop 26.

A. tubular arm 27 is pivote at 19 c oaxially with the lever 18, the mounting of ore los is always in air-tight connection with a 'f pipe 28. The bore of the tubular arm 27- terminates in a relatively minuteleak port 29 against which the valve 25 is arranged to seat so that the valve disc 25 opens and closes the port 29 as it moves in response to changes of length of the hylgroscopic member 16. The tubular arm 27 is angularly adjustable about its fulcrum 19 by turning the key 30. This key operates through a cam mechanism, not shown in detail in the drawing, to produce the desired adjustment of the arm 27. The amount of such adjustment is indicated by a hand 31 which reads against a dial 32. The adjustment of the position of the arm 27 controls the reponse of the instrument to chan'ges of humidity.

The pipe 28 is connected by a port 35 to the space within a corrugated metal diaphragm 36 whose free end is closed by a head 37 against which acts a spring 38 tending to collapse the diaphragm. The range of movement under the action of spring 38 is limited by an internal flange 39 formed' on the head 37. The head 37 is further provided with a projecting stud 40 at its center, which abuts against a valve stem 41 which passes through a packing 42 mounted in a relay valve casing 43.

The casing 43 is provided with an exhaust valve seat 44 and an inlet valve seat 45 at opposite ends of a passage 46. At a point intermediate the seats 44 and 45 a duct 47 leads from the duct 46 by way of a pipe 48 to' the controlled device. This may take various forms but is shown as consisting of a diaphragm motor 49 subject to pressure conveyed by the pipe 48 and acting to open and close a valve 50. The function of the valve 50 is ordinaril to put some airhumidifying or heating evice into and out of action.A

The relay valve consists of an inlet valve 52 urged toward its seat 45 by a spring 53, and an exhaust valve 54 in thrust relation to the inlet valve 52 and provided with a y recess to receive and guide the stem of said valve. "When the diaphragm 36 is collapsed, the valve 52 is closed by the spring 53 and the valve 54 is consequently opened. When the diaphragm 36 is distended it operates through the valve stem 41 to close the exhaust valve 54, and open the inlet valve 52.

The space below the valve 52 is supplied with pressure fluid from a` supply tank 55 through the pipe 56 and duct 57. The space within the relay valve casing above the exhaust valve seat 44 is connected by a duct 58 with a nozzle 59 which discharges across and generally outward through the screen 9. Consequently, the operation of the relay .valve is alternately to admit pressure fluid to the diaphragm motor 49 and then tovdischarge air from the motor 49 against the screen 9. This erforms two functions, the principal one ci) which is to .operate the diaphragm motor 49 and open and close the valve 50. The secondary function is to 'icleanthe screen9 of anyiaccumulated dirt -o'r lint.- f

This cleaning function is particularly important in devicesof a known type in which a current of air from the .room is induced so as to flow in contact-with the hygroscopic element 16. As one familiar means for inducing such flow, I show a tube 60 leading from the duct 57 and serving to discharge air through a nozzle 61 which is alined with the discharge opening 10 in case 6.

Theconstant flow of air upward through the space to the right of the partition 8 leads to the rapid accumulation of dust and .lint ou the lower or entrance side of the screen 9. The air discharged from the nozzle 59 each time the diaphragm motor 49 is vented serves to keep this screen clean.

Air is also supplied from the pipe 56 to the pipe 28, and the space within the diaphragm 36through a minute port 65, interposed between the duct 66 which is in direct communication with the pipe 56, and the duct 67 which is in direct communication with the pipe 28 and duct 35.

The restrictive port consists of a groove in the conical face of a valve-like head '68 which normally seats in a recess formed to receive it. This head 68 is vertically shiftable by means of a rod 69 connected to a head 70 which closes one end of a metallic bellows diaphragm 71. The head 70 is urged upward by a spring 72 and its upward motion is limited by an internal flange 73.

The space Within the diaphragm 71 is in direct communication with the duct 66 and consequently, with the' pressure fluid supply pipe 56. Therefore, when the system is in operation and the supply ipe 56 is under pressure, the diaphragm 1 is distended and the member 68 is held to its seat. When the system is ,shut down and the pressure on the supply pipe 56 is relieved, the diaphragm 71 is collapsed by the spring '72,and the member 68 is moved upward awa from its seat to the osition shown in ig. 4. In moving upwar to this position, it encounters a swab 74 mounted on a spring arm 75, the swab operating to wipe any accumulation of scale or dust from the groove port 65.

lVhen the system is again put into action, the scale or dust so removed will be blown away by the pressure fluid arriving through the duct 66. When the pressure fluid acting with the description and need not be further discussed. Attention is invited, however, to the fact that the means for cleaning port 65 is subject to modification Within the scope of my vclaims and that it is generally susceptible of embodiment in any pressure fluid automatic control device in which a restricted port is used.

Similarly, the screen cleaning mechanism is subject to modification et t'orm within the scope of my claims and .may be applied, whenever useful, to pneumatic control devices of the relay motor type. It is. however, particularly desirable in those devices in which there'is an induced circulation of air as herein described.

As is obvious to those skilled in the art, a thermostatic element or any other element responsive to changes in atmospheric condition may be substituted by the hygroscopic element 16, such substitution being common in this art. Consequently, in the claims I use the phrase responsive element as a generic term to cover this known range. of equivalents.

`What is claimed is 1. The combination of a controlled device ofthe pressure fiuid actuated type; an automatic controlling device connected therewith and including a responsive element and a valve actuating relay motor controlled thereby and serving to admit and exhaust pressure fluid to and from said controlled device; means for inducing a current of air past said responsive element; a screen through Which the entering air current passes; andl mea-ns for directing pressure fluid exhausted by said relay valve against said screen in opposition to said current.

2. The combination of a pressure fluid actuated controlled device; an automatic control device including a responsive element and means actuated thereby to admitI pressure fluid to and exhaust it from said controlled device; a screen protecting said responsive'element from dust and the like While permitting access of air thereto; and screen cleaning means actuated by the pressure fiuid exhausted by said control device.

3. The combination of a pressure fluid actuated controlled device; an automatic control device including a responsive ele' ment and means actuated thereby to admit pressure fluid to and exhaust it from said controlled device; a screen protecting said responsive element from dust and the like While permitting access of air thereto; and means serving to direct the exhaust from said controlled device against said screen to clean the same.

In testimony whereof` I have name to this specification.

WILLIAM B. HODGE.

signed my 

